US3276874A

US3276874A - Photographic developer starter solutions

Info

Publication number: US3276874A
Application number: US274954A
Authority: US
Inventors: Gerald I P Levenson; Clifford J Sharpe
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1963-04-23
Filing date: 1963-04-23
Publication date: 1966-10-04
Anticipated expiration: 1983-10-04

Description

United States Patent 3,276,874 PHOTOGRAPHIC DEVELOPER STARTER SOLUTIONS Gerald I. P. Levenson and Clifford J. Sharpe, Wealdstone,

Harrow, England, assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Apr. 23, 1963, Ser. No. 274,954 3 Claims. (Cl. 96-66) This invention relates to photographic silver halide developer compositions, and in particular to starter solutions for use with liquid developer-replenisher concentrates and to method for their use.

To prevent the working characteristics of a bath of photographic developer from changing seriously during development of a considerable quantity of exposed silver halide photographic material, and also to maintain the volume of the developer, it is common practice to add a replenisher. Such a replenisher is usually a highly concentrated aqueous solution of principal developer constituents that are consumed during development.

Commercial photographic developing baths are sometimes compounded by mixing water and a starter solution, which contains acid and bromide, with a solution thereafter termed developer-concentrate. This concentrate is compounded so that it may be used with the starter for making a developing bath and may also be used alone :or diluted with water, as a replenisher for the developing bath. The starter solution is needed to adjust the initial pH and bromide concentration in the developing bath. An important reason for the use of developer concentrates is the saving in the bulk of liquid to be stored and transported, and for the same reason it is advantageous for starter solutions to be concentrated. Hitherto, starter solutions for use with developer concentrates have been prepared from acetic acid and a soluble bromide such as potassium bromide.

The present invention provides starter solutions for such use that are prepared from hydrobromic acid instead of acetic acid as the source of hydrogen ions. The hydrogen bromide also provides some or all of the bromide ions for the starter solution. A concentration of at least 5% by weight of hydrobromic acid in the solution is preferred.

When more bromide ions are wanted in a starter solution than are provided by the hydrogen bromide, a soluble bromide salt, for example potassium bromide, can be added. It is usually possible to prepare a hydrobromic acid, potassium bromide starter that is more concentrated than one of equal performance would be if made with acetic acid and potassium bromide. Starter solutions prepared with hydrobromic acid are suitable for use with a wide range of developer'concentrates including those designed for developing negative and X-ray films.

The following example gives the formula of a preferred starter and developer-concentrate combination including a starter solution containing hydrogen bromide in accordance with the present invention:

Water to 5 l.

3,276,874 Patented Oct. 4, 1966 ICC Fresh developing solution is prepared by mixing together all of solutions A and B above, and adding Water to make a total volume of 25 liters. A further quantity of the developer-concentrate solution B is prepared for use as a replenisher for the developing bath as needed.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. In a method of making a photographic silver halide developing bath which comprises the step of mixing a developer replenisher solution comprising:

l-phenyl-S-pyrazolidone g 10 Hydroquinone g 300 Borax g Potassium hydroxide g 840 Potassium meta-bisulphite g 1060 Potassium bromide g 20 Water to 5 l.

1-phenyl-3-pyrazolidone g 10 Hydroquinone g 300 Borax o 160 Potassium hydroxide g 840 Potassium metabisulphite g 1060 Potassium bromide g 20 Water to 5 1.

with a starter solution consisting essentially of an acid and bromide ion forming compounds in aqueous solution in about the following proportions 47% by weight hydrobromic acid ml 60 Potassium bromide -gm 40 Water ml 200 the improvement wherein the acid constituent of said starter solution consists essentially of hydrobromic acid.

References Cited by the Examiner Bennett, 0. E.: Abstract of Preparation of Dilute HBr from KBr, Pharm. I. 96, 1916, 293-4.

Petrov et al.: Astract of Equilibria in the System: H O, HBr, and KCl or KBr, Trans. Inst. Pure Chem. Reagents No. 16, 113-17, 1939 (USSR) (C.A. 34: 3568 Wa-sihbunn, E. W.: Ed., International Critical Tables, New York, McGraw-Hill Book Co., Inc., 1928, vol. 3. page 96.

NORMAN G. TORCHIN, Primary Examiner.

C. E. DAVIS, Assistant Examiner.

Claims

1. IN A METHOD OF MAKING A PHTOGRAPHIC SILVER HALIDE DEVELOPING BATH WHICH COMPRISES THE STEP OF MIXING A DEVELOPER REPLENSIHER SOLUTION COMPRISING: 1-PHENYL-3-PYRAZOLIDONE G 10 HYDROQUINOSE G 300 BORAX G 160 POTASSIUM HYDROXIDE G 840 POTASSIUM METABISULPHITE G 1060 POTASSIUM BROMIDE G 20 WATER TO 5 1. WATER TO 5 1. WITH A STARTER SOLUTION WHICH CONTAINS ACID AND BROMIDE ION, THE IMPROVEMENT WHEREIN THE SOLE ACID INGREDIENT OF SAID STARTER SOLUTION CONTAINS HYDROGEN BROMIDE AT A CONCENTRATION OF AT LEAST 5 PERCENT BY WEIGHT OF SAID STARTER SOLUTION.